Encryption and decryption system, encryption device, decryption device and encryption and decryption method

ABSTRACT

An encryption and decryption system includes a first electronic device and a second electronic device. The first electronic device includes a memory device and an encryption device. The memory device can store plaintext data. The encryption device can generate first pseudo data and first pseudo key. The encryption device encrypts first pseudo data by the first pseudo key and encrypt the plaintext data by a key, and outputs the ciphertext data generated by encrypting plaintext data by the key. The second electronic device includes a decryption device for generating second pseudo data and the second pseudo key. The decryption device decrypts the second pseudo data by the second pseudo key, and decrypts the ciphertext data by the key, and outputs the plaintext data, which is generated by decrypting the ciphertext data by the key.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Taiwan Patent Application No.107143838, filed on Dec. 6, 2018, in the Taiwan Intellectual PropertyOffice, the disclosure of which is incorporated herein in its entiretyby reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an encryption and decryptiontechnology, more particularly to an encryption and decryption technologyusing pseudo data and pseudo key, which are generated randomly, toperform pseudo decryption on data.

2. Description of the Related Art

With the advancement of technology, the security of data transmissionbetween electronic devices becomes more and more important, so thatencryption and decryption technology is usually performed on the datatransmission between electronic devices to protect the security of thetransmitted data.

In the conventional data encryption and decryption process, when anelectronic device (A) wants to transmit data to an electronic device(B), in order to prevent the hacker from interpreting transmissionsignals to obtain the data (such as plaintext) transmitted from theelectronic device A to the electronic device B, the electronic device Afirst encrypts the to-be-transmitted data by using the encryptionalgorithm, and after receiving the encrypted data (such as ciphertext),the electronic device B decrypts the encrypted data to obtain theoriginal data.

In recent years, hackers usually perform differential power analysis(DPA) attacks to derive the keys used for encryption and decryption. Inorder to perform the DPA attack, the hacker inputs multiple sets ofplaintexts to activate an internal encryption circuit of a chip togenerate multiple sets of ciphertext, and the hacker can record powertraces of the chip during the encryption process, so as to use therelationship between multiple sets of plaintexts and ciphertext and thepower traces to calculate the possible key. Since the encryption anddecryption algorithm is public, after the hacker obtains the key, thehacker can decrypt the data, which is to be transmitted from theelectronic device (A) to the electronic device (B). Therefore, how toavoid the hackers from using differential energy analysis attacks toobtain the key used for encryption and decryption and from stealing datatransmitted between electronic devices is an important issue in theindustry.

SUMMARY OF THE INVENTION

In order to solve the convention problems, the present inventionprovides an encryption and decryption technology. Particularly, presentinvention provides an encryption and decryption system using pseudo dataand a pseudo key, which are generated randomly, to perform pseudodecryption on data, and an encryption device thereof, a decryptiondevice thereof, and an encryption and decryption method thereof.

According to an embodiment, the present invention provides an encryptionand decryption system comprising a first electronic device and a secondelectronic device. The first electronic device includes a first memorydevice and a first encryption device. The first memory device isconfigured to store plaintext data. The first encryption device isconfigured to generate first pseudo data, generate at least one firstpseudo key, and encrypt the plaintext data by a key and encrypt thefirst pseudo data by the first pseudo key, and output ciphertext datagenerated by encrypting the plaintext data by the key. The secondelectronic device is configured to receive the ciphertext data from thefirst electronic device, and the second electronic device includes afirst decryption device configured to generate second pseudo data and atleast one second pseudo key, and decrypt the ciphertext data by the keyand decrypt the second pseudo data by the at least one second pseudokey, and output the plaintext data generated by decrypting theciphertext data by the key.

According to an embodiment, the present invention provides an encryptiondevice including a random data generator, a random key generator, and anencryption circuit. The random data generator is configured to generatepseudo data. The random key generator is configured to generate at leastone pseudo key. The encryption circuit is coupled to the random datagenerator and the random key generator, and configured to encrypt theplaintext data by the key and encrypt the pseudo data by the firstpseudo key, and output the ciphertext data generated by encrypting theplaintext data by the key.

According to an embodiment, the present invention provides a decryptiondevice including a random data generator, a random key generator and adecryption circuit. The random data generator is configured to generatepseudo data. The random key generator is configured to generate at leastone pseudo key. The decryption circuit is configured to decryptciphertext data by a key, and decrypt the pseudo data by the at leastone pseudo key, and output plaintext data generated by decrypting theciphertext data by the key.

According to an embodiment, the present invention provides an encryptionand decryption method applicable an encryption and decryption system.The method includes following steps: generating first pseudo data, by afirst electronic device; generate at least one first pseudo key, by thefirst electronic device; by the first electronic device, encryptingplaintext data by a key and encrypting the first pseudo data by the atleast one first pseudo key; by the first electronic device, outputtingciphertext data generated by encrypting the plaintext data by the key,to a second electronic device; generating second pseudo data, by thesecond electronic device; generating at least one second pseudo key, bythe second electronic device; and by the second electronic device,decrypting the ciphertext data by the key and decrypting the secondpseudo data by the at least one second pseudo key, to obtain plaintextdata generated by decrypting the ciphertext data by the key.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure, operating principle and effects of the present inventionwill be described in detail by way of various embodiments which areillustrated in the accompanying drawings.

FIG. 1 is a block diagram of an encryption and decryption system 100,according to an embodiment of the invention.

FIG. 2 is a block diagram of a first electronic device 110, according toan embodiment of the invention.

FIG. 3 is a block diagram of a second electronic device 120, accordingto an embodiment of the invention.

FIG. 4 is a block diagram of an encryption device 220, according to anembodiment of the invention.

FIG. 5 is a block diagram of a decryption device 320, according to anembodiment of the invention.

FIG. 6 is a flowchart 600 of an encryption and decryption method,according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following embodiments of the present invention are herein describedin detail with reference to the accompanying drawings. These drawingsshow specific examples of the embodiments of the present invention.These embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the invention to thoseskilled in the art. It is to be acknowledged that these embodiments areexemplary implementations and are not to be construed as limiting thescope of the present invention in any way. Further modifications to thedisclosed embodiments, as well as other embodiments, are also includedwithin the scope of the appended claims. These embodiments are providedso that this disclosure is thorough and complete, and fully conveys theinventive concept to those skilled in the art. Regarding the drawings,the relative proportions and ratios of elements in the drawings may beexaggerated or diminished in size for the sake of clarity andconvenience. Such arbitrary proportions are only illustrative and notlimiting in any way. The same reference numbers are used in the drawingsand description to refer to the same or like parts.

It is to be acknowledged that, although the terms ‘first’, ‘second’,‘third’, and so on, may be used herein to describe various elements,these elements should not be limited by these terms. These terms areused only for the purpose of distinguishing one component from anothercomponent. Thus, a first element discussed herein could be termed asecond element without altering the description of the presentdisclosure. As used herein, the term “or” includes any and allcombinations of one or more of the associated listed items.

It will be acknowledged that when an element or layer is referred to asbeing “on,” “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layer,or intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present.

In addition, unless explicitly described to the contrary, the word“comprise” and variations such as “comprises” or “comprising”, will beacknowledged to imply the inclusion of stated elements but not theexclusion of any other elements.

Please refer to FIG. 1, which is a block diagram of an encryption anddecryption system 100 according to an embodiment of the invention. Asshown in FIG. 1, the encryption and decryption system 100 can include afirst electronic device 110 and a second electronic device 120. Itshould be noted that the first electronic device can be regarded as anencryption end and the second electronic device can be regarded as adecryption end when data is transmitted from the first electronic deviceto the second electronic device; alternatively, the second electronicdevice can be regarded as an encryption end and the first electronicdevice can be regarded as a decryption end when the data is transmittedfrom the second electronic device to the first electronic device. Forillustration of this embodiment of the present invention, the firstelectronic device is regarded as the encryption end and the secondelectronic device is regarded as the decryption end; however, thepresent invention is not limited thereto.

Please refer to FIG. 2, which is a block diagram of the first electronicdevice 110 according to an embodiment of the invention. As shown in FIG.2, the first electronic device 110 can include a first central processor210, an encryption device 220, a first direct memory access (DMA) 230, afirst memory device 240 and a first communication device 250. It shouldbe noted that the block diagram of FIG. 2 is merely for convenience inexplanation of the embodiment of the present invention, but the presentinvention is not limited thereto; for example, the first electronicdevice 110 can include other component. Furthermore, according to anembodiment of the present invention, the first central processor 210,the encryption device 220, the first DMA 230, the first memory device240 and the first communication device 250 can be integrated in amicrocontroller (MCU). It should be noted that the first electronicdevice 110 can also include a decryption device, which is not shown inFIG. 2. According to an embodiment of the present invention, thedecryption device of the first electronic device 110 and the encryptiondevice 220 can be integrated in the same circuit. According to anotherembodiment of the present invention, the decryption device of the firstelectronic device 110 and the encryption device 220 can be implementedby two independent circuits. The architecture of the decryption deviceof the first electronic device 110 can also refer to that of thedecryption device 320 shown in FIG. 5.

Please refer to FIG. 3, which is a block diagram of the secondelectronic device 120 according to an embodiment of the invention. Asshown in FIG. 3, the second electronic device 120 can include a secondcentral processor 310, a decryption device 320, a second DMA 330, asecond memory device 340 and a second communication device 350. Itshould be noted that the block diagram of FIG. 3 is merely forconvenience in explanation of the embodiment of the present invention,but the present invention is not limited thereto; for example, thesecond electronic device 120 can include other component. Furthermore,according to an embodiment of the present invention, the second centralprocessor 310, the decryption device 320, the second DMA 330 and thesecond memory device 340 can be integrated in a microcontroller. Itshould be noted that the second electronic device 120 can also includean encryption device, which is not shown in FIG. 4. According to anembodiment of the present invention, the encryption device of the secondelectronic device 120 and the decryption device 320 can be integrated inthe same circuit. According to another embodiment of the presentinvention, the encryption device of the second electronic device 120 andthe decryption device 320 can be implemented by two independentcircuits, respectively. The architecture of the encryption device of thesecond electronic device 120, can also refer to the encryption device220 shown in FIG. 4.

According to an embodiment, in order to transmit plaintext data P1 fromthe first electronic device 110 to the second electronic device 120, thefirst central processor 210 informs the encryption device 220 of amemory address of the plaintext data P1 to be transmitted and a memoryaddress for storing ciphertext data C1. Next, the encryption device 220triggers the first DMA 230 and informs the first DMA 230 of the memoryaddress of the plaintext data P1 to be transmitted and the memoryaddress of the output data. After the first DMA 230 is triggered, thefirst DMA 230 instructs the first memory device 240 to transmit theplaintext data P1 to the encryption device 220, according to the memoryaddress of the plaintext data P1 to be transmitted. After the encryptiondevice 220 encrypts the plaintext data P1, the encryption device 220stores the generated ciphertext data C1 to the first memory device 240according to the memory address for storing the ciphertext data C1. Thefirst DMA 230 can read the ciphertext data C1 from the first memorydevice 240 according to the memory address for storing the ciphertextdata C1, and the first communication device 250 can transmit theciphertext data C1 to the second communication device 350 of the secondelectronic device 120. The encryption device 220 can use an encryptionalgorithm to perform encryption operation. In an embodiment, theencryption algorithm can be a symmetric encryption algorithm, such as anadvanced encryption standard (AES) algorithm, but the present inventionis not limited thereto. Furthermore, the details of the process of theencryption device 220 encrypting the plaintext data P1 will beillustrated with reference to FIG. 4.

According to another embodiment of the present invention, the firstcentral processor 210 can directly instruct the first memory device 240to transmit the plaintext data P1 to the encryption device 220, and thefirst central processor 210 can directly read the ciphertext data C1from the first memory device 240, and the first communication device 250can transmit the ciphertext data C1 to the second communication device350 of the second electronic device 120.

Please refer to FIG. 4, which is a block diagram of an encryption device220 according to an embodiment of the invention. As shown in FIG. 4, theencryption device 220 can include a first random data generator 410, afirst random key generator 420, a first data mixer circuit 430, a firstkey mixer circuit 440 and an encryption circuit 450.

As shown in FIG. 4, the first data mixer circuit 430 of the encryptiondevice 220 can obtain the plaintext data P1 from the first memory device240, and the first key mixer circuit 440 of the encryption device 220can obtain the key K1 for encrypting the plaintext data P1. In anembodiment, the key K1 can be pre-stored in a temporary storage deviceof the encryption device 220 (not shown in FIG. 4) or the first memorydevice 240.

After the encryption device 220 receives the plaintext data P1, thefirst random data generator 410 generates pseudo data P2. The pseudodata P2 contains at least one piece of sub pseudo data. According to anembodiment of the present invention, the length of each piece of subpseudo data of the pseudo data P2 is the same that of the plaintext dataP1, but the present invention is not limited thereto. The pseudo data P2is also transmitted to the first data mixer circuit 430. After the firstdata mixer circuit 430 receives the plaintext data P1 and the pseudodata P2, the first data mixer circuit 430 randomly arranges theplaintext data P1 and the pieces of the sub-data of and the pseudo dataP2, to generate first input data P_(IN). The first data mixer circuit430 can transmit the generated first input data P_(IN) and the sequenceinformation of the plaintext data P1 and the pseudo data P2 arranged inthe first input data P_(IN), to the encryption circuit 450.

Furthermore, after the encryption device 220 receives the plaintext dataP1, the first random key generator 420 can generate a pseudo key K2. Thepseudo key K2 contains at least one sub pseudo key. According to anembodiment of the present invention, each sub pseudo key corresponds toa piece of the sub pseudo data. According to another embodiment of thepresent invention, the plurality of pieces of sub pseudo data can sharethe same sub pseudo key. The generated pseudo key K2 is transmitted tothe first key mixer circuit 440. After the first key mixer circuit 440receives the key K1 and the pseudo key K2, the first key mixer circuit440 can mix the key K1 and the pseudo key K2 to generate a first inputkey K_(IN1). The first key mixer circuit 440 transmits the generatedfirst input data P_(IN) and the sequence information of the key K1 andthe pseudo key K2 arranged in the first input key K_(IN1), to theencryption circuit 450.

After the encryption circuit 450 receives the first input data P_(IN),the sequence information of the plaintext data P1 and the pseudo data P2arranged in the first input data P_(IN), the first input key K_(IN1),and the sequence information of the key K1 and the pseudo key K2arranged in the first input key K_(IN1), the encryption circuit 450 canuse the key K1 to encrypt the plaintext data P1 and use the pseudo keyK2 to encrypt the pseudo data P2, according to the sequence informationof the plaintext data P1 and the pseudo data P2 arranged in the firstinput data P_(IN), and the sequence information of the key K1 and thepseudo key K2 arranged in the first input key K_(IN1). After theplaintext data P1 and the pseudo data P2 are encrypted completely, theencryption circuit 450 outputs the ciphertext data C1, which isgenerated by encrypting the plaintext data P1 by the key K1, to thefirst memory device 240. Next, according to the memory address of theoutput data, the first DMA 230 can read the ciphertext data C1 from thefirst memory device 240, and the first communication device 250 cantransmit the ciphertext data C1 to the second communication device 350of the second electronic device 120.

After the second communication device 350 of the second electronicdevice 120 receives the ciphertext data C1, the second central processor210 informs the decryption device 320 of the memory address of storingthe ciphertext data. C1 and the memory address for storing the decryptedplaintext data P1. Next, the decryption device 320 triggers the secondDMA 330, and informs the second DMA 330 of the memory address of theciphertext data C1 to be decrypted and the memory address for storingthe decrypted plaintext data P1. After the second DMA 330 is triggered,the second DMA 330 can instruct the second memory device 340 to transmitthe ciphertext data C1 to the decryption device 320 according to thememory address of the ciphertext data C1 to be decrypted. After thedecryption device 320 decrypts the ciphertext data C1 completely, thedecryption device 320 can store the plaintext data P1, which isgenerated by decrypting the ciphertext data C1, to the second memorydevice 340 according to the memory address for storing the decryptedplaintext data P1. The decryption device 320 can use a decryptionalgorithm to perform decryption operation. in an embodiment, thedecryption algorithm can be a symmetric encryption algorithm, such as anadvanced encryption standard algorithm, but the present invention is notlimited thereto. The details of the process of the decryption device 320decrypting the ciphertext data C1 will be illustrated in followingparagraph with reference to FIG. 5.

FIG. 5 is a block diagram of a decryption device 320 according to anembodiment of the invention. As shown in FIG. 5, the decryption device320 can include a second random data generator 510, a second random keygenerator 520, a second data mixer circuit 530, a second key mixercircuit 540 and a decryption circuit 550.

As shown FIG. 5, the second data mixer circuit 530 of the decryptiondevice 320 can obtain the ciphertext data C1 from the second memorydevice 340, and the second key mixer circuit 540 of the decryptiondevice 320 can obtain the key K1 for decrypting the ciphertext data C1.In an embodiment, the key K1 can be pre-stored in a temporary storagedevice (not shown in FIG. 5) of the decryption device 320 or in thesecond memory device 340.

After the decryption device 320 receives the ciphertext data C1, thesecond random data generator 510 can generate the pseudo data C2. Thepseudo data C2 can contain at least one piece of sub pseudo data.According to an embodiment of the present invention, the length of eachpiece of the sub pseudo data of the pseudo data C2 is the same as thatof the plaintext data P1, but the present invention is not limitedthereto. The pseudo data C2 is also transmitted to the second data mixercircuit 530. After the second data mixer circuit 530 receives theciphertext data C1 and the pseudo data C2, the second data mixer circuit530 randomly arranges the ciphertext data C1 and the pieces of sub-dataof and the pseudo data C2, to generate second input data C_(IN). Thesecond data mixer circuit 530 then transmits the generated second inputdata C_(IN) and the sequence information of the ciphertext data C1 andthe pseudo data C2 arranged in the second input data C_(IN), to thedecryption circuit 550.

Furthermore, after the decryption device 320 receives the ciphertextdata C1, the second random key generator 520 generates a pseudo key K3.The pseudo key K3 can contain at least one sub pseudo key. According toan embodiment of the present invention, each sub pseudo key correspondsto a piece of sub pseudo data. According to another embodiment of thepresent invention, the plurality of pieces of sub pseudo data can sharethe same sub pseudo key. The generated pseudo key K3 is transmitted tothe second key mixer circuit 540. After the second key mixer circuit 540receives the key K1 and the pseudo key K3, the second key mixer circuit540 mixes the key K1 and the pseudo key K3 to generate a second inputkey K_(IN2). The first key mixer circuit 440 transmits the generatedsecond input key K_(IN2) and the sequence information of the key K1 andthe pseudo key K3 arranged in the second input key K_(IN2), to thedecryption circuit 550.

After the decryption circuit 550 receives the second input data C_(IN),the sequence information of the ciphertext data C1 and the pseudo dataC2 arranged in the second input data C_(IN), the second input keyK_(IN2), and the sequence information of the key K1 and the pseudo keyK3 arranged in the second input key K_(IN2), the encryption circuit 450can use the key K1 to decrypt the ciphertext data C1 and use the pseudokey K3 to decrypt the pseudo data C2 according to the sequenceinformation of the ciphertext data C1 and the pseudo data C2 arranged inthe second input data C_(IN), and the sequence information of the key K1and the pseudo key K3 arranged in the second input key K_(IN2). Afterdecrypting the ciphertext data C1 and the pseudo data C2 completely, thedecryption circuit 550 outputs the plaintext data P1, which is generatedby decrypting the ciphertext data C1 by the key K1, to the second memorydevice 340.

FIG. 6 is a flowchart 600 of an encryption and decryption methodaccording to an embodiment of the invention. The encryption anddecryption method can be applicable to the encryption and decryptionsystem 100 of the present invention, and includes steps S610 to S670. Ina step S610, the first electronic device of the encryption anddecryption system 100 generates the at least one piece of first pseudodata. In a step S620, the first electronic device of the encryption anddecryption system 100 generates the at least one first pseudo key. In astep S630, the first electronic device of the encryption and decryptionsystem 100 encrypts the plaintext data by a key and encrypts the firstpseudo data by the first pseudo key. In a step S640, the firstelectronic device of the encryption and decryption system 100 outputsthe ciphertext data, which is generated by encrypting the plaintext databy the key, to the second electronic device of the encryption anddecryption system 100. In a step S650, the second electronic device ofthe encryption and decryption system 100 generates the at least onepiece of second pseudo data. In a step S660, the second electronicdevice of the encryption and decryption system 100 generates the atleast one second pseudo key. In a step S670, the second electronicdevice of the encryption and decryption system 100 decrypts theciphertext data by the key and decrypts the second pseudo data by thesecond pseudo key, so as to obtain plaintext data generated bydecrypting the ciphertext data by the key.

During the encryption and decryption process of the encryption anddecryption method provided in the embodiment of the present invention,the pseudo data and the pseudo key are generated to mix with the truedata and the true key for further encryption and decryption process. Asa result, a hacker possibly records wrong power trace and cannotcalculate the possible key. According to embodiment of the presentinvention, the encryption and decryption method of the present inventioncan prevent the encryption/decryption key from being stolen by thehacker using differential energy analysis attack, so as to protect thedata transmitted between electronic devices from being stolen.

The steps of method and algorithm disclosed in the specification of thepresent invention can be directly executed by a processor to directlyapply to a hardware module, a software module or a combination thereof.A software module can include an execution command and relate data, andthe software module and other data can be stored in a data memory suchas RAM memory, a flash memory, a ROM memory, an erasable programmableROM memory, an electrically erasable programmable ROM memory, aregister, a hard disk, a portable hard disk, a CD-ROM, a DVD or othercomputer readable storage medium well known in the art. A storage mediumcan be coupled to a machine device such as a computer/processor, and forconvenience in explanation, the processor is taken as an example of themachine device in the present disclosure, and the processor can readdata (such as program codes) from and write data into the storagemedium. The storage medium can be integrated with the processor. Anapplication-specific integrated circuit (ASIC) includes the processorand the storage medium. A user device can include theapplication-specific integrated circuit. In other words, the processorand the storage medium can be included in the user device but notdirectly connected to the user device. Furthermore, in some embodiments,the product suitable for the computer program can include a readablestorage medium, wherein the readable storage medium includes the codesrelated to at least an embodiment of the present invention. In someembodiments, the product suitable for the computer program can includepackage material.

The present invention disclosed herein has been described by means ofspecific embodiments. However, numerous modifications, variations andenhancements can be made thereto by those skilled in the art withoutdeparting from the spirit and scope of the disclosure set forth in theclaims.

What is claimed is:
 1. An encryption and decryption system, comprising:a first electronic device comprising: a first memory device configuredto store plaintext data and a key; and a first encryption deviceconfigured to generate first pseudo data and generate at least one firstpseudo key; and a second electronic device comprising: a second memorydevice; and a first decryption device configured to generate secondpseudo data and at least one second pseudo key, wherein the firstencryption device generates a first input data according to theplaintext data and the first pseudo data, wherein the first encryptiondevice generates a first input key according to the key and the at leastone first pseudo key, wherein according to the first input data and thefirst input key, the first encryption device encrypts the plaintext databy the key to generate a ciphertext data and encrypts the first pseudodata by the at least one first pseudo key, wherein the first encryptiondevice outputs the ciphertext data to the second electronic device,wherein the first decryption device generates a second input dataaccording to the ciphertext data and the second pseudo data, wherein thefirst decryption device generates a second input key according to thekey and the at least one second pseudo key, wherein according to thesecond input data and the second input key, the first decryption devicedecrypts the ciphertext data by the key to generate the plaintext dataand decrypts the second pseudo data by the at least one second pseudokey, and wherein the first decryption device outputs the plaintext datato the second memory device.
 2. The encryption and decryption systemaccording to claim 1, wherein the first electronic device comprises asecond decryption device, and the second electronic device comprises asecond encryption device.
 3. An encryption device, comprising: a randomdata generator configured to generate pseudo data; a random keygenerator configured to generate at least one pseudo key; and anencryption circuit coupled to the random data generator; a data mixercircuit coupled to the random data generator and the encryption circuit,and configured to mix plaintext data and the pseudo data to generateinput data; and a key mixer circuit coupled to the random key generatorand the encryption circuit, and configured to mix a key and the at leastone pseudo key to generate an input key, wherein according to the inputdata and the input key, the encryption circuit encrypts the plaintextdata by the key to generate a ciphertext data and encrypts the pseudodata by the at least one first pseudo key, wherein the encryption deviceoutputs the ciphertext data; wherein the data mixer circuit transmitsthe input data, and first sequence information of the plaintext data andthe pseudo data arranged in the input data, to the encryption circuit,and the key mixer circuit transmits the input key, and second sequenceinformation of the key and the pseudo key arranged in the input key, tothe encryption circuit and wherein the encryption circuit encrypts theplaintext data and the pseudo data according to the input data, thefirst sequence information of the plaintext data, the input key, and thesecond sequence information of the key.
 4. A decryption device,comprising: a random data generator configured to generate pseudo data;a random key generator configured to generate at least one pseudo key;and a decryption circuit; a data mixer circuit coupled to the randomdata generator and the decryption circuit, and configured to mixciphertext data and the pseudo data to generate input data; and a keymixer circuit coupled to the random key generator and the decryptioncircuit, and configured to mix a key and the at least one pseudo key, togenerate an input key, wherein according to the input data and the inputkey, the decryption circuit decrypts the ciphertext data by the key togenerate plaintext data and decrypts the second pseudo data by the atleast one second pseudo key, and wherein the decryption circuit outputsthe plaintext data; wherein the data mixer circuit transmits the inputdata and first sequence information of the ciphertext data and thepseudo data arranged in the input data, to the decryption circuit, andthe key mixer circuit transmits the input key and second sequenceinformation of the key and the pseudo key arranged in the input key, tothe decryption circuit and; wherein the decryption circuit decrypts theciphertext data and the pseudo data according to the input data, thefirst sequence information of the ciphertext, the input key, and thesecond sequence information of the key.
 5. An encryption and decryptionmethod, applicable an encryption and decryption system and comprising:generating first pseudo data, by a first electronic device; generatingat least one first pseudo key, by the first electronic device;generating, by the first electronic device, a first input data accordingto plaintext data and the first pseudo data; generating by the firstelectronic device a first input key according to a key and the at leastone first pseudo key; according to the first input data and the firstinput key, encrypting, by the first electronic device, the plaintextdata by the key to generate a ciphertext data and encrypts the firstpseudo data by the at least one first pseudo key; outputting, by thefirst electronic device, the ciphertext data to a second electronicdevice; generating second pseudo data, by the second electronic device;generating at least one second pseudo key, by the second electronicdevice; generating, by the second electronic device, a second input dataaccording to the ciphertext data and the second pseudo data; generating,by the second electronic device, a second input key according to the keyand the at least one second pseudo key; and according to the secondinput data and the second input key, decrypting, by the secondelectronic device, the ciphertext data by the key to generate theplaintext data and decrypting the second pseudo data by the at least onesecond pseudo key.